Electronic circuit for converting polar to rectangular co-ordinates



A ril 28, 1964 s. w. GATES ETAL 3,131,297

ELECTRONIC CIRCUIT FOR CONVERTING POLAR TO RECTANGULAR CO-ORDINATESOriginal Filed Feb. 25, 1958 4 Sheets-Sheet 1 NN,- Z F/6Z 1 ANTENNATRANSMITTER NEcE/vE/g r/N/Na, CODING, Em I I 22 I RANGE I) INFORMATIONPL/L-s E ANGLE 12 a /4 M POI REF VOLTAGE ANGLE /NE POLAR COBRDINATEINFO.

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5 PHASE zNrENs/rr PICK-OFF P/CK-OF NEFLE'c- 4N0 r/0N AMI? 48 STORAGESTORAGE 0/17/1005 A) TUBE INVENTOR. She/don W Gafes By John M. SanbomeMW l A'LZC/ Apnl 28, 1964 s. w. GATES ETAL 3,131,297 ELECTRONIC CIRCUITFOR CONVERTING POLAR TO RECTANGULAR CO-ORDINATES Original Filed Feb. 25,1958 4 Sheets-Sheet 5 s .53 g. m w w W .llllllllllnll. Ill-I'll I w .C bs Q 1 r J E M9 22 W 1? I I I I III C v mwwfimmwmw kmm wvww wmw Q i. i Wn n C 1 m T M m K I m R v v N W i m hm *m x R in i EESCQ b EE CQESQ 7 WPIII N W RQWL l.l \vwfi est Q m a w 3 mfibm Mum Q ENG $5 a T 8% m bsmwtwe wms |..l||| I- lllll .Illl 7 i 8, 1964 s. w. GATES ETAL 3,

ELECTRONIC CIRCUIT FOR CONVERTING POLAR TO RECTANGULAR CO-ORDINATESOriginal Filed Feb. 25. 1958 4 Sheets-Sheet 4 MQEEE $3 I. E25 5 M gan mE II 0G mm in RE m Ea v E 55E EQE 7W DS IIIII'IL 55 l llll By John M.Sanborne United States Patent 3,131,297 ELECTRONIC CIRCUIT FOR CONVERTWG POLAR Ti) RECTANGULAR CO-QENATES Sheldon W. Gates and John M.Sanborne, Phoenix, assignors to Motorola, Inc, Chicago, ill., acorporation of Illinois Continuation of appiication Ser. No. 717,499,Feb. 25, 1958. This application Jan. 12, 1962, Ser. No. 168,001 8Claims. (Cl. 235-189) This invention relates to electronic apparatus toperform the analogue operation of converting polar coordinateinformation to rectangular coordinate information. This is a.continuation of our application Serial No. 717,499, filed February 25,1958, now abandoned.

In present day electronic computers and radar equipment it is frequentlynecessary to convert polar coordinate signal information into signalsusable in a rectangular coordinate system. This conversion involves thecomputation of x and y in the equations x=A cosine 6; y=A sine 0, whereA and 0 are given.

The system of this invention is concerned with the utilization of twotime spaced pulses representing A, or vector magnitude, and two timespaced pulses representing 0 or vector angle, and the .conversion ofthese two sets of pulses into two signals representing ordinate andabscissa quantities for representation of the vector in Cartesiancoordinates, that is in which one end of the vector is located at anaxis intersection and the other end of the vector is represented by theordinate and abscissa quantities. The two sets of polar coordinatepulses for conversion in the system of the invention can be produced invarious ways, the choice of which can be primarily determined by theoverall system in which the conversion system is used. In order toillustrate one way in which the invention has been successfullyused, itwill be described in a radar system in which information in polarcoordinates is converted to rectangular coordinates for display on acathode ray tube.

In such a radar application the time spacing of transmitted pulses andechos can represent the range information, or magnitude of A directly,and antenna angle can supply the target angle or azimuth with respect toa reference antenna position, which represents 0. Conversion of thispolar coordinate information into rectangular coordinate signals maythen be desirable for application to the electrostatic deflection systemof a cathode ray tube.

Prior systems for providing rectangular coordinate signals have requiredmechanical or servo means to establish both range and angle informationin a rectangular coordinate system, as well as various associatedcircuits along with the mechanical or servo means, all of which tend tointroduce errors into the conversion operation. Aside from suchinaccuracies which may be developed in the mechanical conversion ofrange and angle information, such apparatus may also be of considerablesize and weight rendering it less suitable for some applications such asin aircraft.

An object of the present invention is to provide an electronicconversion system wherein radar range information may be used directly,thus preserving accuracy, and only relatively accurate mechanicaloperation is required to obtain the necessary angular information.

Another object is to provide an electronic system for converting timemodulated polar coordinate information into rectangular coordinateinformation with a high degree of accuracy.

Another object is to provide a system for converting polar coordinateinformation into rectangular coordinate signals which can be displayedby a cathode ray tube,

3,131,297 Patented Apr. 28, 1964 and which system can be constructed ina form which is compact and of light weight.

A feature of the invention is the provision of an electronic coordinateconversion system utilizing time spaced pulses to establish theamplitude of a ringing signal representing vector magnitude, whichringing signal is divided into signals displaced by 90 and sampledaccording to angle information in the form of time spaced pulses.

Another feature of the invention is the provision of such a coordinateconversion system wherein angle information in the form of time spacedpulses, for exanr ple, produced by a linear potentiometer operated by aradar antenna with the potentiometer controlling a pulse time modulator,operating through bidirectional diode bridge gates controls sampling oftwo ringing signals phase displaced by 90 to establish vector angle.

Another feature is the provision of such a coordinate conversion systemutilizing linear bidirectional bridge gates, triggered by means ofprecise control circuits, for controlling a ringing circuit to establishthe amplitude of a ringing signal representing vector magnitude and forcontrolling the sampling instant of the ringing signal to insureaccuracy of coordinate conversion.

Further objects, features and the attending advantages of the inventionwill be apparent upon consideration of the following description whentakenin conjunction With the accompanying drawings in which:

FIG. 1 is a block diagram showing the coordinate conversion system as itmay be utilized in a radar system;

FIG. 2 is a set of graphs useful in explaining the operation of theconversion system;

FIGS. 3 and 4 are schematic diagrams of the conversion system of theinvention.

In the coordinate conversion system of the invention, time spaced pulsesrepresenting vector magnitude and time spaced pulses representing vectorangle, are converted to rectangular (Cartesian) coordinate informationwhich may. be used tocontrol the electrostatic deflection system of acathode ray tube for visual display of the information. The vectormagnitude information can be direct range information from radarinterrogation and echo pulses, while the vector angle information can bederived by a potentiometer system operated by the radar antenna, whichpotentiometer system controls a pulse-time modulator. In the conversionof the time modulated pulses, the capacitor of a tuned circuit, orringing circuit,-is charged through a bidirectional diode bridge gate toa potential representing vector magnitude and the ringing circuit isallowed to ring through a bidirectional diode bridge gate for a fixedperiod at the established amplitude. A phase shifting network isutilized to form two signals phase displaced by and having amplituderepresenting the vector magnitude. These two signals are sampled throughbidirectional diode bridge gates at an instant corresponding to vectorangle and the sampled value represents Cartesian coordinate informationwhich may be used for electrostaticdefiection in a cathode ray tube fordisplay purposes.

The system of the present invention will be described as it is used in aparticular application, although other applications will be apparent tothose familiar with the art. The following brief description of theradar system in block form in FIG. 1 is to show one way of utilizing thepolar-to-rectangular coordinate conversion system of the invention andwill serve to illustrate how pairs of pulses representing polarcoordinate information can be generated for use in the conversion systemwhich is shown in detail in FIGS. 3 and 4. In FIG. 1 the leads markedangle start pulse and angle stop pulse are intended to indicate theleads on which a pair of pulses are applied, the spacing between whichrepresents the angular position of a vector; and the leads marked rangestart pulse and range stop pulse are intended to indicate the leads towhich are applied a pair of pulses the spacing between which representsvector magnitude.

' In FIG. 1 there is shown a radar system including a motor drivenrotatable antenna 16) which is designed to turn through 360. This isconnected to suitable transmitter-receiver apparatus 12 which isarranged to transmit pulses and receive echos from a target to providerange information in the form of time modulated pulses such as rangestart pulse 15 and range stop pulse 15 as shown in FIG. 2.

Antenna rotates in synchronisrn with angle potentiometer 18 across whicha reference voltage is applied from the direct current voltage source20. A pulse time modulator circuit 22 is connected to the arm of thepotentiometer 18 and to the transmitter-receiver apparatus 12 and thismodulator circuit is arranged to provide time spaced pulses representingthe angular position of the antenna. These are shown in FIG. 2 as anglestart pulse 24 and angle stop pulse 25. It may be noted that thetransmittenreceiver apparatus 12 would include suitable timing circuitsso that in any given position of the antenna 10 the necessary rangepulses and azimuth pulses may be obtained in the sequence shown in FIG.2.

General Operation of Polar t0 Rectangular Coordinate Conversion SystemThe range start pulse and the range stop pulse 16 (FIG. 2), the timespacing between which represents vector magnitude and in the case ofradar represents target distance, are applied via leads 13 and 14 to therange demodulator 32 which develops a linear ramp that is maintained ata D.C. value 34 which is directly related to the time separation betweenthe range pulses. This D.C. value 34 is maintained until the othercircuits have performed their function.

The DC. value 34 is used to establish the operating level, or magnitudeof oscillations, in a variable amplitude ringing circuit 38. As will bedescribed in greater detail subsequently, the direct current potentialrepresenting vector magnitude, or range, charges a capacitor in theringing circuit, the energy from which is used in an oscillating tunedcircuit. The angle start pulse (it being understood that this is one ofa pair of pulses representing vector angle) is also applied to theringing circuit 38 on lead 19, and as shown in FIG. 2, this start pulse24 occurs after the range stop pulse 16 to trigger the ringing circuitand provide a sine wave 40 having an amplitude related to the DC value34, that is, the vector magnitude.

Ringing circuit 38 is connected to a divider and phase shift circuit 42which provides a leading sine wave 44 and a lagging sine wave 45 whichare respectively leading sine wave 40 by 45 and lagging sine wave 40 by45. It may be noted that the signals 44, 45 are displaced in phase by 90and that these signals would trace a circle if applied to the deflectionplate of a cathode ray tube, and that this circuit would have a radiusrepresenting target range or vector magnitude.

The leading ring or wave 44 is applied to a pick-off and storage circuit48 and the lagging ring or wave 45 is applied to a pick-off and storagecircuit 50. Circuits 48 and 50 received angle stop pulse 25 onlead 21(this pulse being the other pulse in the representation of vector angle)and these circuits include suitable storage capacitors which willmaintain potentials corresponding to the instantaneous amplitudes of thewaves 44 and 45 when stop pulse 25 occurs. The instantaneous amplitudeof wave 44 is designated 44a in FIG. 2 and that of signal 45 isdesignated 45a. The potential levels 44a and 45a are coupled todeflection amplifiers 52 which are connected to the electrostaticdeflection plates of cathode ray tube 54. Suitable intensity modulationmay be applied to the cathode ray tube when signals represented bypotentials 4411 and 45a are applied to the deflection plates in order tobrighten the screen at this time and produce a spot which will representthe original polar coordinate information as it has been converted intosignals representing rectangular or Cartesian coordinates. The intensitymodulation pulse 56 is shown in FIG. 2.

Vector Magnitude Demodulator of the Conversion System multi-vibratorcircuits to provide square wave control gates for the bootstrap chargingcircuit. The width of these control gates is such as to insure propercircuit function consistent with time division with other stations in anentire system and consistent with a predetermined maximum range for theapparatus.

Range start pulse 15 is applied to the blocking oscil lator 60 whichincludes a pair of triodes 62 and 63. The triodes 52, 63 are normallycut off but are driven into conduction when the pulse 15 is applied tothe grid of tube 62. Feedback is utilized in the oscillator 60 to insurea positive response to the start pulse. The output of the oscillator 60is applied to monostable rnultivibrator '71) which includes triodes 73and 74. Triode 73 is normally conducting and triode 74 is normally cutoil. However, when the signal from oscillator 60 is applied to the anodeof triode 74, the conditions are reversed and triode 73 is cutoff, withtriode 74 then conductive. The output of the 'multivibrator 70 isderived from the anode of triode 74 and is coupled through blockingcapacitor '77 and applied to the control grid of the starting gatetriode 8d. Triode is normally conductive with its conduction pathextending between C-minus at its cathode, through resistor 83 and diode93 to ground. However, when the negative going pulse is applied togating triode 81) this tube becomes out 01f. Prior to cut off of triode80, the voltage on bootstrap capacitor 91 was maintained atapproximately zero by means of clamp diode 93 connected thereacross.However, as starting gate triode S0 is cut off, capacitor 91 commencesto charge through diode 85, resistor 87 and diode 89. Diode 89immediately is cut off by the rising voltage at the cathode of cathodefollower and the charging power for capacitor 91 is obtained from thecathode follower triode 95. Due to bias circuits of triodes 112, 114,these triodes are cut off at this time.

The anode of triode 95 is connected to B-plus and its cathode isconnected through resistor 97 to C-minus. The grid of this tube isconnected to the junction of bootstrap capacitor 91 and the cathode ofdiode 85. The cathode of triode 95 is also connected through capacitor100 to the junction of resistor 87 and the cathode of diode 89.Accordingly, as capacitor 91 commences to charge, the voltage at thecathode of triode 95 rises and the voltage at the top of resistor 87 israised in accordance with the instantaneous potential on capacitor 91.This action maintains a constant voltage across resistor 87 and thuscapacitor 91 charges linearly.

During the linear charge of capacitor 91 the range stop pulse 16 isapplied to the blocking oscillator 102. Pulse 16 thereby drives normallycut oil triodes 104 and 105 into conduction. The output derived from theanodes of these two tubes in the blocking oscillator circuit is suppliedto the anode of triode 157 in the monostable multivibrator 109. Triode111 in the circuit 159 is normally conductive and triode 167 is normallycut off. However, as the signal is applied from blocking oscillator 102,the

conduction condition reverses and triode 111 is cut off with triode 107conductive.

During the charging of capacitor 91 triodes 112 and 114 are in a cut oifcondition. A triggering pulse for tube 112 is derived from the feedbacktransformer 114 in the blocking oscillator 192, and this is a positivegoing pulse to drive tube 112 into conduction thus lowering its anodepotential and lowering the potential of the anode of diode 85 which isconnected thereto. Accordingly, diode 85 is cut off which thusinterrupts the charging of capacitor 91, and this capacitor maintainsits charge.

A positive going pulse is also derived from the anode of triode 111 inthe multivibrator 109. This is applied to the grid of triode 114 causingthis tube to conduct and further the action of triode 112.

At the cathode of cathode follower triode 95, there appears a directcurrent potential which is proportional to the time separation of therange start and stop pulses and this potential represents the vectormagnitude or radar range. Utilization of this potential will be eX-plained in connection with the diagram of FIG. 4. As shown in FIG. 1,the potential is applied to the variable amplitude ringing circuit 38and is maintained until after the occurrence of angle start pulse 24.Then, consistent with time sharing in the system, collapse of thesignals from multivibrators 7%, 109 causes return to the previouslydescribed normal condition of the circuits.

Vector Angle Demodulator of the Conversion System In FIG. 4, the directcurrent potential representing vector magnitude is applied to the gridof triode 125 in the cathode follower circuit 127. The potential thusestablished at the cathode of triode 125 is applied through thebi-directional linear diode gate 129 to the capacitor 131. The capacitoris charged in direct proportion to the direct current output voltage ofthe range demodulator 32.

The angle start pulse 24 is applied to the cathode of triode 133 in themonostable multivibrator 135. In the normal condition triode 137 is cutoff and triode 133 is conductive. However, as the angle start pulse isapplied to the multivibrator 135, this conduction condition reverses andtriode 137 is conducting while triode 133 is cut off.

The anode of triode 133 is connected to diode 138 in the gate circuit129 and the anode of triode 137 is con nected to the diode 139 in thisgate circuit. The gate 129 is a six diode bridge gate which is a rapidaction switch and causes the capacitor 131 to be disconnected from thecathode of triode 125 in response to angle start pulse 24.

In the conducting condition of gate 129, diodes 138 and 139 are biasedto cut-off and diodes 140, 141, 142 and 143, connected in a bridgecircuit, are conductive between C-minus and B-plus through resistors 144and 145. An input signal applied to the interconnection of diodes 140,141 is transferred as a corresponding signal in an output circuitconnected to the junction of diodes 142 and 143. In this way capacitor131 is charged through the diode bridge gate 129. When the angle startpulse 24 occurs, a positive going pulse is applied to diode 138 and anegative going pulse is applied to diode 139, causing these diodes to beconductive through resistors 144 and 145, respectively, thereby cuttingoif diodes 141i and 143 as well as diodes 141 and 142. Additional diodebridge gates 157, 175 and 180 described subsequently, also operate in acorresponding manner in response to the trigger pulses applied thereto.

A capacitor 131 is charging, inductor 15's) and resistor 151 are seriesconnected thereacross. Resistor 151 is made large enough to effectivelyisolate the inductor from the charging circuit.

The angle start pulse 24 also causes immediate closing of the normallyopen gate 157, thereby connecting capacitor 131 and inductor 150directly in parallel in the ringing circuit. Gate 157 is triggered intoa conduction condition by means of the pulses applied to diodes 153 and155 from tubes 133 and 137, respectively. As previously pointed out, theamplitude of the ringing signal is direct- 1y proportional to vectormagnitude. Resistor 151 provides a dissipation path for inductor 150when the ringing signal has been used and gate 157 is again open.

It may be seen therefore, that capacitor 131 charges from a lowimpedance source, that is, cathode follower 127 through the normallyclosed gate 129, so that the capacitor is eifectively connected betweenground and the cathode of tube 125, which is connected through resistor159 to C-minus. At this time, gate 157 is open. However, when theringing operation commences, gate 129 is opened simultaneously with theclosing of gate 157 which directly couples one side of inductor 150 toground. This is a desirable relationship of the gate 157 and the ringingcircuit since a gate circuit of this type possesses an impedance toground when in a conducting condition, and in the system described, bothsides of gate 157 are at ground potential during the ringing operation.

It is further pointed out that as capacitor 131 and inductor 150 areringing, the instantaneous potential at the junction thereof may benegative with respect to ground. For this reason multivibrator providesa pulse to cut off diode 139 which is negative with respect to ground.This is obtained by returning the cathode of triode 133 to the C-minussource. To further improve the operation of the system and the speed ofresponse thereof thus preventing undesirable duty-cycle errors,multivibrator 135 is direct current coupled to the diode gates 129 and157. The energization circuits of triodes 133 and 137 therefore includeconnections of the cathodes thereof to the C-minus potential andconnections of the anodes thereof to the B-plus potential.

In the utilization circuit for the ringing signal, the junction ofcapacitor 131 and inductor is connected to the grid of triode in thecathode follower circuit 162. The output of circuit 162 is connected tothe input of cathode follower 164 and the input of cathode follower 165.The input circuit for cathode follower 164 includes a series connectedcapacitor 166 and resistor 168 with the input signals applied to triode167 from across the resistor of this input network. Accordingly, theoutput from circuit 164 leads the input signal by 45. The input networkto cathode follower includes a series connected resistor 170 andcapacitor 171 with the input to triode 169 being derived from across thecapacitor, so that the output of cathode follower 165 lags the inputsignal by 45. The signal from cathode follower 165 is designated 44 inFIG. 2 and that from cathode follower 64 is designated 45 in thatfigure.

The signal from cathode follower 164 is applied through the normallyconducting diode bridge gate 175 and across storage capacitor 177.Similarly, the output of cathode follower 165 is applied through thenormally conducting diode bridge gate 189 and across the storagecapacitor 182.

When the angle stop pulse 25 occurs, it is applied to the cathode oftriode 137 in the monostable multivibrator 186. Normally, triode 184 iscut off and triode 187 is conducting. However, the angle stop pulsecauses triode 187 to be cut off and triode 184 to conduct. The anode oftriode 184 is connected to diode 18? in gate and diode 191 in gate 175.A ne ative going pulse is applied to diodes 189, 191. The anode oftriode 187 is connected to diode 194 in gate 180 and to diode 195 ingate 175. A positive going-pulse is applied to these diodes, and bothpositive and negative going pulses from the multivibrator 186 causegates 17 5 and 180 to be nonconductive. This leaves capacitors 177and182 with respective instantaneous potentials 45a and 44a as shown inFIG. 2. These potentials are then derived from the terminals shown andapplied to suitable deflection amplifiers 52 as shown in 'FIG. 1. Whenthe pulses from multivibrators 135, 186 collapse, the circuits return tothe described normal state and the entire conversion system may bereoperated.

Therefore, in response to the angle start pulse 24 and the angle stoppulse 25, the ringing signals 14 and 45 are produced in the proper phaseand started at the proper time so that their respective instantaneousvalues at the time of the angle stop pulse 25 will represent the vectorangle or radar target azimuth. The use of the bidirectional linear gates129 and 157 provide control of the ringing circuit 131, 1513 with a highdegree of accuracy, While at the same time affording a desirable dampingof the circuit during charging of the condenser. However, when thecircuit is ringing or oscillating these gates by their arrangement inthe circuit, offer an extremely high damping resistance thereby insuringaccuracy of the amplitude of the ringing signal. The use of gates 175and 1% also provide highly accurate and efiicient control of the storagecapacitors 177 and 182 which furnish the output potentials of thecoordinate convergence system.

Accordingly, this invention may be used to perform the conversion frompolar coordinate information, in the form of time modulated pulses, toCartesian coordinate information in the form of a pair of controlpotentials. The system is particularly adapted for use in conjunctionwith radar apparatus where it may be employed in a system as shown anddescribed in a manner to minimize the need for relying upon mechanicalapparatus in forrning the range and angle information into suitablesignals for use with display apparatus. Therefore, the system permitsthe construction of compact, lightweight radar equipment.

\Ve claim:

1. An electronic circuit for converting signal information representinga vector quantity in polar coordinates into a pair of potentialsrepresenting such quantity in rectangular coordinates, said circuitincluding in combination, circuit means for producing a direct currentpotential proportional to vector magnitude, a ringing circuit forproducing a first sine wave having an amplitude proportional to thedirect current potential, circuit means for producing second and thirdsine waves in 90 phase relation and having amplitudes proportional tothat of the first sine wave, circuit means for sampling theinstantaneous values of the potentials of the second and third sinewaves at a time of the respective periods thereof corresponding tovector angle, whereby such potentials represent the vector quantity inrectangular coordinates.

2. An electronic circuit for converting first time spaced pulsesrepresenting vector magnitude and second time spaced pulses representingvector angle into signals representing rectangular cordinateinformation, said circuit including in combination, circuit means forproducing a direct current potential proportional to the time spacing ofthe first pulses, a ringing circuit controlled by the direct currentpotential to produce a first sine wave having an amplitude proportionalto vector magnitude, circuit means for producing second and third sinewaves in 90 phase relation and having amplitudes proportional to that ofthe first sine wave, circuit means for sampling the instantaneous valuesof the second and third sine waves according to the time modulation ofthe second pulses, and display means for utilizing the aforesaidinstantaneous values of the second and third sine waves as rectangularcoordinate information.

3. An electronic circuit for converting first time spaced pulsesrepresenting vector magnitude and second time spaced pulses representingvector angle into potentials representing rectangular coordinateinformation, said circuit including in combination, demodulator circuitmeans for producing a direct current potential proportional to the timedifference between the first and second pulses, a tuned circuitincluding capacitor and inductor means, first gating circuit meanscoupling said capacitor means to said demodulator circuit means forcharging said capacitor means according to the value of the directcurrent potential, said first gating circuit means being responsive tothe third pulse to couple said tuned circuit in oscillatory relation fordeveloping a sine wave having an amplitude proportional to vectormagnitude, phase shift circuit means for producing first and secondringing signals in phase relation and having amplitudes proportional tothe amplitude of the sine wave, second gating circuit means, and firstand second storage capacitor means adapted to be coupled to said phaseshift circuit means through said second gating circuit means, saidsecond gating circuit means being responsive to the fourth pulse forcharging said first and second storage capacitor means to respectivepotentials representing the instantaneous values of the first and secondringing signals, which potentials represent rectangular coordinateinformation.

4. An electronic system for displaying polar coordinate information in acathode ray tube, including in combination, circuit means providingfirst and second pulses time spaced to represent vector magnitude, apotentiometer system, mechanical means operating said potentiometersystem according to vector angle, an angle pulse time modu lator coupledto said circuit means and said potentiometer system to produce third andfourth pulses time spaced to represent vector angle and following saidfirst and sec- 0nd pulses, demodulat-ing circuit means for producing adirect current potential proportional to the time difference between thefirst and second pulses, a tuned circuit including capacitor andinductor means, first gating circuit means coupling said capacitor meansto said demodulator circuit means for charging said capacitor meansaccording to the value of the direct current potential, said firstgating circuit means being responsive to the third pulse to couple saidtuned circuit in oscillatory relation for developing a sine Wave havingan amplitude proportional to vector magnitude, phase shift circuit meansfor producing first and second ringing signals in 99 phase relation andhaving respective amplitudes proportional to the amplitude of the sinewave, second gating circuit means, first and second storage capacitormeans adapted to be coupled to said phase shifting circuit means throughsaid second gating circuit means, said second gating circuit means beingresponsive to the fourth pulse for charging said first and secondstorage capacitor means to respective potentials representing theinstantaneous values of said first and second ringing signals, andcathode ray display apparatus having beam deflection means coupled tosaid storage capacitor means for control of an electron beam thereby anddisplay of the coordinate information.

5. An electronic system for converting polar coordinate information inthe form of first and second time spaced pulses representing vectormagnitude and third and fourth time spaced pulses representing vectorangle, into rectangular coordinate information, said system including incombination linear capacitor charging circuit means including a firstcapacitor and circuit means responsive to the first pulse for chargingsaid first capacitor toward a potential increasing directly with theinstantaneous charge thereon, said capacitor charging circuit meansincluding a circuit responsive to the second pulse for interrupting thechanging of said first capacitor and maintaining the charge thereon, aringing circuit including series coupled inductor means and resistormeans and second capacitor means, a first diode bridge gate coupledbetween said capacitor charging circuit means and said second capacitormeans for applying a potential across said second capacitor means whichis proportional to the potential on said first capacitor, said firstdiode bridge gate being subject to open circuit in response to the thirdpulse for interrupting the charging of said second capacitor means, asecond diode bridge gate connected across said resistor means, saidsecond diode bridge gate being subject to shunt said resistor means andcouple said inductor means and said second capacitor means inoscillatory relation so that the same produces a first sine Wave signalhaving an amplitude proportional to the time spacing of the first andsecond pulses, a first phase shift circuit to produce a second sine Wavesignal leading said first sine wave signal by 45, a second phase shiftcircuit to produce a third sine Wave signal lagging said first sine Wavesignal by 45, third and fourth diode bridge gates, first and secondstorage capacitor means, said third diode bridge gate being coupledbetween said first phase shift circuit and said first storage capacitormeans, said fourth diode bridge gate being coupled between said secondphase shift circult and said second storage capacitor means, said thirdand fourth diode bridge gates being subject to open circuit in responseto the fourth pulse, whereby said first and second storage capacitormeans are charged to respective potentials representing rectangularcoordinate information, and means (for utilizing said respectivepotentials as a representation of the coordinate information.

6. An electronic system for converting polar coordinate information, inthe form of first and second time spaced pulses representing vectormagnitude and third and fourth time spaced pulses representing vectorangle, into rectangular coordinate information, said system including incombination linear capacitor charging circuit means to provide apotential proportional to the time spacing of the first and secondpulses, a ringing circuit including series coupled inductor means,resistor means and second capacitor means, a first gating circuitcoupling said capacitor charging circuit means to said ringing circuitfor applying a potential across said second capacitor means which isproportional to the vector magnitude, said first gating circuit beingsubject to open circuit in response to the third pulse for interruptingthe charging of said second capacitor means, a second gating circuitconnected across said resistor means, said second gating circuit beingsubject to shunt said resistor means and couple said inductor means andsaid second capacitor means in oscillatory relation to produce a firstsine wave signal having an amplitude proportional to vector magnitude, afirst phase shift circuit to produce a second sine wave signal leadingsaid first sine wave signal by a second phase shift circuit to produce athird sine Wave signal lagging said first sine Wave signal by 45, thirdand fourth gating circuits, first and second storage capacitor means,said third gating circuit being coupled between said first phase shiftcircuit and said first storage capacitor means, said fourth gatingcircuit being coupled between said second phase shift circuit and saidsecond storage capacitor means, said third and fourth gating circuitsbeing subject to open circuit in response to the fourth pulse, wherebysaid first and second storage capacitor are charged to respectivepotentials representing rectangular coordinate information, and meansfor utilizing said respective potentials as a representation of thecoordinate information.

7. In an electronic system for controlling sine wave signals, thecombination of an input circuit providing a direct current potential ofcertm'n value, capacitor means, a first diode bridge gate coupling saidcapacitor means to said input circuit, inductor means, a second diodebridge gate coupling said inductor means across said capacitor means, acontrol circuit coupled to said first and second diode bridge gates,said control circuit providing a pa tential for initially closing saidfirst gate and opening said second gate for changing said capacitormeans to the direct current potential, said control circuit furtherproviding pulses for simultaneously opening said first gate and closingsaid second gate for coupling said capacitor means and inductor means inoscillatory relation for producing a sine Wave signal having anamplitude of the certain value, and circuit means coupled to saidcapacitor means and inductor means for utilizing the sine wave signal.

8. The electronic system of claim 7 in which said input circuit includesa cathode follower direct current coupled to said first diode bridgegate, and said control circuit includes a monostable multivibratordirect current coupled to said first and second diode bridge gates.

No references cited.

1. AN ELECTRONIC CIRCUIT FOR CONVERTING SIGNAL INFORMATION REPRESENTINGA VECTOR QUANTITY IN POLAR COORDINATES INTO A PAIR OF POTENTIALSREPRESENTING SUCH QUANTITY IN RECTANGULAR COORDINATES, SAID CIRCUITINCLUDING IN COMBINATION, CIRCUIT MEANS FOR PRODUCING A DIRECT CURRENTPOTENTIAL PROPORTIONAL TO VECTOR MAGNITUDE, A RINGING CIRCUIT FORPRODUCING A FIRST SINE WAVE HAVING AN AMPLITUDE PROPORTIONAL TO THEDIRECT CURRENT POTENTIAL, CIRCUIT MEANS FOR PRODUCING SECOND AND THIRDSINE WAVES IN 90* PHASE RELATION AND HAVING AMPLITUDES PROPORTIONAL TOTHAT OF THE FIRST SINE WAVE, CIRCUIT MEANS FOR SAMPLING THEINSTANTANEOUS VALUES OF THE POTENTIALS OF THE SECOND AND THIRD SINEWAVES AT A TIME OF THE RESPECTIVE PERIODS THEREOF CORRESPONDING TOVECTOR ANGLE, WHEREBY SUCH POTENTIALS REPRESENT THE VECTOR QUANTITY INRECTANGULAR COORDINATES.